The present invention relates to a storage device system (hereafter referred to as a storage system) for storing data used by a computer, and more particularly relates to a storage system comprising a controller and a recording medium controlled by the controller in which the data block size handled by the controller and the data block size handled by the recording medium are different.
A disk array system is a type of storage system connected to a computer. Disk array systems, which are also known as RAID (Redundant Array of Inexpensive Disks) systems, constitute storage systems that comprise a plurality of disk devices arranged in an array and a controller for controlling said. Disk array systems, based on the parallel operation of the plurality of disk devices, facilitate the high-speed processing of read requests (hereafter referred to as read requests) and data write requests (hereafter referred to as write requests) and, in addition, the imparting of redundancy to data. Disk arrays systems, as is disclosed in D. Patterson and 2 others, “A case for Redundant Arrays of Inexpensive Disks (RAID)”, ACM SIGMOD Conference Proceeding, June 1988, p. 109-116 (Non-patent Document), are classified into five levels on the basis of the type of data to which redundancy has been imparted and the configuration thereof.
Redundant data is produced in disk array systems in such a way that data can be restored when damage to a disk device occurs, and the redundant data is stored in disk devices different to those for the data. However, with the objective of further increasing the reliability of the disk array system as a whole, guarantee codes are sometimes added to the logic blocks stored in the disk devices. A description of guarantee codes is given in, for example, U.S. Pat. No. 5,819,054 and U.S. Pat. No. 5,706,298. In the guarantee code of U.S. Pat. No. 5,819,054, a logical address (hereafter LA (Logical Address) of the logic block designated by the computer in the accessing of a logic block and an LRC (Longitudinal Redundancy Check) obtained by the implementation of an exclusive OR operation on the logic block data are added to the logic block and the guarantee code and logic block are stored in the disk device. The LA and LRC are employed as error detection codes for detecting address errors in the storage region in which the logic block data is written and detection errors in the logic block data respectively.